IP multicasting is the most efficient way to perform group data distribution, as it eliminates traffic redundancy and improves bandwidth utilization. Application Layer Multicast (ALM) has been proposed to overcome some of the limitations in IP multicasting such as scalability and deploy-ability. Limited computing power, scarcity of bandwidth and end-host?s reluctance to share bandwidth make ALM difficult to spread. In this paper, we keep eye to those problems and present an ALM that scrutinizes the commitment of the ALM nodes. Failure to provide quality of service agreement triggers performance penalty for the node in concern. Thus, every node has an obligation to its descendants; as a result, a nice collaboration among the end-hosts is achieved for group communication. It has good performance for content distribution, as it reflects physical network topology onto the overlay network constructed by the end-hosts. Tree refinement and backup path strategies are taken to better satisfy heterogeneous QoS requirements.